Recently, a number of platinum complexes have been shown by Rosenberg and co-workers to be highly active anti-tumor agents. [U.S. Pat. Nos. 4,177,263 and 4,140,707.] The complex, cis-dichlorodiammine-platinum-II, is the chemotherapeutic agent of choice in the treatment of many and varied tumors.
There are several drawbacks associated with the use of the platinum complexes to treat tumors, however. Generally, the platinum complexes have a relatively low solubility in water thereby rendering it difficult to formulate a composition which can effectively deliver the reagent to the site of the tumor in the body.
Moreover, many of the platinum complexes are highly nephrotoxic thereby further restricting their use in the absence of precautionary measures to avoid damage to the kidneys when administered to animals afflicted with tumors.
Additionally, platinum complexes and cis-dichlorodiammine-platinum-II in particular are relatively inactive against gastro-intestinal tumors, presumably because of an inability to aquate in the presence of the high chloride concentrations present in this region of the body.
It is an object of the present invention to provide certain novel palladium complexes, pharmaceutical compositions comprising certain palladium complexes and methods for the treatment of tumors with certain palladium complexes which do not share the disadvantages associated with the platinum complexes of the prior art.